Researchers have discovered life-size rock carvings of camels, gazelles and other animals in Saudi Arabia. The carvings date back around 12,000 years and many are over 6 feet tall. Scientists say they were created using a wedge-shaped rock to make sharp lines. Scientists weren’t sure if humans lived in the desert during this time period since conditions were dry and water was scarce. The art and tools show that people lived in the area about 2,000 years earlier than previously thought, though it's not yet clear how they survived. The findings were published Tuesday in the journal Nature Communications.